JPH0126262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a strobe device useful as an artificial light source during photography, and more particularly to a power wastage prevention device that prevents power source batteries from being wasted.

As a conventional device that can prevent power wastage, when it is not used for a long time, it charges the capacitor.
The base current of the transistor that operates the DC-DC converter is cut off, and this transistor is turned off to stop the operation of the DC-DC converter.
A device has been proposed that prevents power wastage by doing so (Japanese Patent Laid-Open No. 50-62734). this is,
If the DC-DC converter is not used for a long time, charging the capacitor cuts off the base current of the transistor that powers the DC-DC converter, turning off this transistor and stopping the operation of the DC-DC converter, thereby reducing the power supply. Prevents waste.

However, this method uses a separate delay circuit to measure the time when it is not in use, and as the delay circuit operates, the capacitor is charged.
In addition to a capacitor to turn off the transistor that activates or deactivates the DC-DC converter circuit, a delay circuit is required.
There are problems in that the circuit configuration becomes complicated and the cost also increases.

The present invention has been made to solve this problem, and will be described below with reference to the drawings.

The figure is an electric circuit diagram of a strobe device showing an embodiment of the present invention. In the figure, 1 indicates resistors 10, 11,
14, 15, a timer circuit consisting of transistors 12, 16, and a capacitor 13; 2, a well-known circuit consisting of an oscillation transistor 17, an oscillation transformer 18, etc.
DC-DC converter circuit, 3 is a trigger circuit consisting of a trigger capacitor 20, synchro switch 21, trigger transformer 19, resistor, etc., 4 is a main capacitor, 5 is a flash discharge tube, 6 is a capacitor 2
2, a reset circuit consisting of resistors 23, 24, and a transistor 25; 7, a power source that is a battery; and 8, a shutter release lock mechanism (not shown) is linked and turned on to force the operation of the DC-DC converter circuit 2. lock switch, 9
26 is a normally open starting switch constituted by, for example, a touch switch, and 26 is a resistor.

In the configuration as described above, the start switch 9
When the capacitor 13 is turned on, the charge in the capacitor 13 that has been charged through the resistors 10 and 11 by the power supply 7 is discharged, and current starts flowing through the resistors 10 and 11 again. This current continues until charging of the capacitor 13 is completed after the start switch 9 returns to its original state. That is, the operation of the timer circuit 1 is such that the resistors 10, 1
The operation is to flow a current through 1.

When current flows through resistors 10 and 11, transistor 12 becomes conductive, and current flows through resistors 14 and 15. Therefore, the transistor 16 is made conductive, and the current flowing through the transistor 16 is supplied as the base current of the oscillation transistor 17 of the DC-DC converter circuit 2, and the DC-DC converter circuit 2 is Start operation.

When the DC-DC converter circuit 2 starts operating, the main capacitor 4, trigger capacitor 20, and capacitor 22 are charged.

As mentioned earlier, this charging operation continues until the capacitor 13 of the timer circuit 1 is completely charged, that is, until the transistor 12 can no longer be kept conductive due to the current flowing through the resistors 10 and 11. It will be done. That is, after the predetermined time set by the timer circuit 1 has elapsed, the base current of the oscillation transistor 17 is no longer supplied, so that the DC
- The DC converter circuit 2 stops operating, and each of the capacitors except for the trigger capacitor 20, which had been charged up to that point, starts to self-discharge, and finally each capacitor is brought to its initial uncharged state.
Incidentally, when the energy supply from the DC-DC converter circuit 2 runs out, the trigger capacitor 20
As is clear from the drawing, the connection is such that the charge that has been charged up to that point is instantly released via the resistor, that is, this embodiment is a DC
- At the same time as the operation of the DC converter circuit 2 stops, the flash light emission operation becomes impossible.

On the other hand, when the synchro switch 21 in the trigger circuit 3 is closed while the DC-DC converter circuit 2 is in operation and the main capacitor 4 etc. are in a charged state where they can emit light. , the charge in the trigger capacitor 20 is transferred to the trigger transformer 19 and the synchro switch 2.
1, so the trigger transformer 1
The flash discharge tube 5 is triggered by a high-voltage pulse generated on the secondary side of the flash discharge tube 9, consumes the charge in the main capacitor 4, and emits light.

The operation as described above is the basic operation of the illustrated embodiment. By instantaneously cutting off the energy supply from the power supply without having to operate the DC-DC converter circuit for a period of time, it becomes possible to use the power supply more effectively, and the lock switch 8 and resistor 26 perform this function. .

As is clear from the drawing, this lock switch 8 connects the capacitor 13 to both ends of the power supply 7 via the resistor 26 when it is closed, and the time constant for charging the capacitor 13 by the power supply 7 at this time is It is set to be extremely short. Therefore, in terms of operation, when the lock switch 8 is closed, charging of the capacitor 13 is immediately completed, that is, the timing operation of the timer circuit 1 is ended, and the operation of the DC-DC converter circuit 2 is as follows. This means that the system will shut down in no time, preventing unnecessary energy usage. The lock switch 8 shuts off energy consumption when it is closed, and if it is configured to be easily closed, it may cause disadvantages.For example, when it is attached to a camera, Needless to say, consideration should be given to interlocking the operation of a lock mechanism or the like that controls the state.

Next, the strobe device of the present invention has a reset circuit, and the reset circuit 6 will be briefly described above.

Although the above-described timer circuit 1 and lock switch 8 can achieve the purpose of preventing waste of power, in the case of a strobe device, considering the usage conditions, in most cases it is desired to perform light emitting operation continuously. Therefore, if the timer circuit 1 and the like according to the present invention is configured with a focus on preventing waste of power, it will be necessary to operate the start switch 9 every time the light is emitted, which is rather cumbersome when considering the overall handling of the device. It is possible that this will happen.

For this reason, the reset circuit 6 is constructed and its operation is as follows.

That is, at the same time that the flash discharge tube 5 emits light, the charge stored in the capacitor 22 is transferred to the flash discharge tube 5,
Since it is emitted through the resistors 23 and 24, the resistor 2
The voltage drop across 4 causes transistor 25 to become conductive. Since the transistor 25 is connected in parallel with the capacitor 13, when the transistor 25 is made conductive by the above operation, the capacitor 1
3 charge will be instantly discharged. That is, the state is exactly the same as when the start switch 9 is turned on, and therefore the capacitor 13
Charging is started, and of course the operation of the DC-DC converter circuit 2 is also restarted.

As described above, the reset circuit 6 returns the timer circuit 1 to a state in which it can start timing operation when the flash discharge tube 5 emits light, and eliminates the above-mentioned troublesome handling. be.

As described above, the strobe device of the present invention uses DC-
It maintains and stops the operation of the DC converter circuit, and since no separate delay circuit is provided, the circuit configuration can be made simple and inexpensive.

[Brief explanation of drawings]

The figure is an electrical circuit diagram showing an embodiment of a strobe device according to the present invention. 1... Timer circuit, 2... DC-DC converter circuit, 3... Trigger circuit, 4... Main capacitor, 5... Flash discharge tube, 6... Reset circuit, 7
...Power source, 8...Lock switch, 9...Start switch, 10, 11...Resistor, 13...Capacitor, 12, 16...Transistor, 17...Oscillation transistor.

Claims (1)

[Claims] 1. A power supply battery, a DC-DC converter circuit that includes an oscillation transformer, an oscillation transistor, etc., and that boosts the voltage of the power supply battery to charge a main capacitor, and a flash discharge tube that emits light by consuming the charge of the main capacitor. , a trigger circuit that triggers the flash discharge tube, and a first switching element provided in the base current supply loop of the oscillation transistor;
It has a capacitor charged by the power supply battery via a first resistor and a second switching element, and the second switching element is made conductive by the current flowing through the first resistor while the capacitor is being charged. It consists of a timer circuit that makes the first switching element conductive, a normally open start switch connected in parallel to the capacitor, a series circuit of a second resistor whose resistance value is lower than that of the first resistor, and a lock switch; a circuit connected in parallel to the first resistor for rapidly charging the capacitor of the timer circuit; a third switching element connected in parallel to the normally open switch; and a circuit for generating a voltage as the flash discharge tube emits light; A strobe device comprising a reset circuit comprising a voltage generating circuit that applies a voltage to a third switching element to make the third switching element conductive.